Robotic Cleaners simply plug into a standard 110v GFCI receptacle, just drop it in the pool and turn it on, no hoses to connect. Robotic Cleaners work independently of your pools filter system so you don't need to run your filter for it to work.
Suction side cleaners
A suction side cleaner has a hose that connects to your thru-wall skimmer, you will need to run your pool filter for it to operate. While not as simple to use as a Robotic Cleaner, Suction Side Cleaners are a good low cost alternative.